Gaseous discharge device



Get. 26, 1937. P. L... SPENCER SEOUS DISCHARGE DEVICE Original Filed Oct. 7, 1929 P871] Z. INVENTOR.

A TTORNEK Patented Oct. 26, 1937 UNITED STATES PATENT OFFICE cAsaoUs mscnaaca DEVICE Application October 7, 1929, Serial No. 397,881 Renewed May 3, 1937 9 Claims.

This invention relates to gaseous discharge device. The invention generally relates to a device in which a gaseous discharge. is initiated or stopped by the action of light. The invention finds its simple and most useful embodiment in the form of a tube having a glass or similar transparent envelope on the inside of which is formed a photoelectric coating. Mounted within the device is an anode of any shape whatsoever and 10 a cathode of the ordinary type useful in glow discharges. Any suitable gas preferably of the rare group is introduced up to a pressure of about 2 m. m.

The photoelectric coating and anode are preferably connected to a source of potential in the ordinary manner and under the same conditions as a photoelectric tube. The glow discharge cathode, however, is connected to the negative pole of a source of potential having a value about equal to the running potential of the device as a glow discharge lamp. This running potential is substantially less than the voltage necessary to start a glow discharge in the device in absence of auxiliary starting means.

Under such conditions, upon the impingement of light on the photoelectric coating, the electron emission is sufficient to ionize the gaseous region within the tube and permit a discharge to pass between the glow discharge cathode and anode. As is well known in such a glow discharge tube as I have shown, the ionization of the gas in the tube upon the passage of a discharge is quite copious, and is sufficient to produce enough positive ions to substantially neutralize the space charge. Due to this fact, when a discharge is initiated, practically no control can be exerted upon the discharge merely by such a member emitting electrons as the photo-electric coating of my device. Therefore the mere absence of light on the photoelectric coating would be of no avail whatever in reversing the process and destroying the discharge. In order that control may be efficiently exercised in the reverse phase, I preferably have capacity and inductance in the circuit so related as to result in oscillations being generated. In this way, with the use of direct current, the glow discharge flickers while the light impinges upon the photoelectric coating. As soon as the light is removed the photoelectric coating fails to perform its function of aiding in starting up the lamp. I

A lamp of this character may be used directly on alternating current of suitable potential without the necessity of an oscillating circuit. Provision in the form of a resistance is made for .of photoelectric material. ly done by heating capsule 1 so that the chemicals preventing the photoelectric coating carrying too heavy a current and thus being destroyed by bombardment.

A system of the above character may be very effectively used to control and actuate alternating current relays to control powerful sources of energy, In this way the necessity for powerfully amplifying the output of a photoelectric tube in order to make it available for relay purposes is entirely obviated.

10 Referring to the drawing, the figure shows a tube partly broken away connected to a suitable system.

The photoelectric tube is preferably, though not necessarily, made as disclosed in my copending 15 application Serial No. 321,472, filed November 23,

1928. As disclosed and. claimed in the above entitled case, I have a glass envelope I of any suitable shape. Sealed in a stem 2 is a wire 3 terminating in a ring anode l. This anode carries some lumps 5 of metallic magnesium. The tube is first thoroughly exhausted. Anode B is suitably heated by high frequency induction means or the like so that the magnesium is vaporized and caused to condense upon the interior surface of l. A window 6 may thereafter be outlined by local heating, as by a hand torch. Thereafter the magneslum layer is oxidized and covered with a coating This may be effectivetherein interact. The chemicals are preferably the bichromate of the photoelectrically active metal, such as caesium, mixed with metallic silicon. After obtaining the layer of photoelectrically active material, the envelope is-filled with a rare gas such as neon, helium or argon at apressure of about 2 m. m. or less. A wire 8 sealed in the wall of I terminates in a cap 9 to connect the photoelectric coating.

Supported by wires sealed in press 2 is'a cylin- 4o drical cathode ll! of nickel or any other suitable material. One of the supports 'for this cathode terminates in a wire l3. An ordinary vacuum tube base l4 may be cemented to the tube and in such case wires 3 and I3 are soldered to two pins 4.". l6 and I5 of the base. The remaining pins are dead. Capsule 1 may be supported by wire I! welded to cathode l2. It should be noted that during the formation of the photoelectric active coating on the interior surface of the glass wall H that a similar coating will also be formed on the surface of the cathode l2 and this tends to make a low cathode drop.

Anode A of the tube is connected through a resistance 2| of about 100,000 ohms to the posipreferably of the order of 2 to 10 megohms. This resistance is to prevent any considerable current from passing through the photoelectric coating. A condenser 25 is bridged directly across the cathode and anode of the device.

With the direct source of current shown, the lamp when going will oscillate and tend to flicker. Hence, the photoelectric tube effectively functions at the beginning of each flicker. In this way, the absence of light serves to stop the discharge within the period of an oscillation.

The relay may control any desired mechanism. The entire system is susceptible to many uses such as the automatic opening of doors upon the flashing of light, the control of devices in accordance with the time of the day, such as beacons inthe ocean, etc.

I claim:

1. A gaseous discharge device comprising a glass vessel, a layer of magnesium on the inside surface thereof, said magnesium having its surface oxidized, a layer of photoelectrically active material on said oxidized magnesium surface, a gas filling, an anode, and a glow discharge cathode.

2. A photo-electric device comprising a gastight vessel containing an anode, a glow discharge cathode, a gas filling at a pressure sumcient to produce copious ionization thereof suflicient to substantially neutralize space charge upon the passage of a discharge between said cathode and anode, means for starting an ionizing discharge between said cathode and anode at a voltage less than the normal starting voltage, said means comprising photo-electric means separate from said anode and cathode and disposed adjacent the discharge path between said anode and cathode and adapted to emit electrons into said discharge path upon excitation by light radiations entering .said device from the exterior of said vessel.

3. A photo-electric device comprising a gastight vessel containing an anode, a glow discharge cathode, a gas filling at a pressure sumcient to produce copious ionization thereof sufiicient to substantially neutralize space charge upon the passage of a discharge between said cathode and anode, and means for starting a glow discharge between said anode and cathode, said means comprising photo-electric means separate from said anode and cathode and disposed adjacent the discharge path between said anode and cathode and adapted to emit electrons into said discharge path upon excitation by light radiations entering said device from the exterior of said vessel, whereby the potential necessary to start a discharge between said anode and cathode is lowered sufliciently so that a discharge can start upon the application of a voltage between said cathode and anode of the order of the normal running potential of said device, the voltage necessary to start such a discharge, in absence .of such excitation, being substantially higher than said normal running potential.

4. A photo-electric device comprising a gastight vessel containing an anode, a glow discharge cathode, a gas filling at a pressure sufiicient to produce copious ionization thereof sufiicient to subtantially neutralize space charge upon the passage of "a discharge between said cathode and anode, means for starting a glow discharge between said anode and cathode, said means comprising photo-elec'tric means separate from said anode and cathode and disposed adjacent the dischargepath between said anode and cathode and adapted to emit electrons into said discharge path upon excitation by light radiations entering said device from the exterior of said vessel, whereby the potential necessary to start a discharge between said anode and cathode is lowered sufiiciently so that a discharge can start upon the application of a voltage between said cathode and anode of the order of the normal running potential of said device, the voltage necessary to start such a discharge, in absence of such excitation, being substantially higher than said normal running potential, and means for establishing electrical connections from the exterior of said envelope to said anode, cathode, and photo-electric means.

5. A photo-electric device comprising a gastight vessel containing a relatively small-area anode, a relatively large-area glow discharge cathode, a gas filling at a pressure sufficient to produce copious ionization thereof sufficient to substantially neutralize space charge upon the passage of a discharge between said cathode and anode, and means for starting a glow discharge between said anode and cathode, said means comprising photo-electric means separate from said anode and cathode and disposed adjacent the discharge path between said anode and cathode and adapted to emit electrons into said discharge path upon excitation by light radiations entering said device from the exterior of said vessel, whereby the potential necessary to start a discharge between said anode and cathode is lowered sufliciently so that a discharge can start upon the application of a voltage between said cathode and anode of the order of the normal running potential of said device, the voltage necessary to start such a discharge, in absence of such excitation, being substantially higher than said normal run-. ning potential.

6. A photo-electric device comprising a gastight vessel containing an anode, a glow discharge cathode, a gas filling at a pressure suflicient to produce copious ionization thereof suflicient to substantially neutralize space charge upon the passage of a discharge between said cathode and anode, means for starting an ionizing discharge between said cathode and anode at a voltage less than the normal starting voltage, said means comprising photo-electric means separate from said anode and cathode and disposed adjacent the discharge path between said anode and cathode and adapted to emit electrons sumcient to produce ionization in said discharge path upon excitation by light radiations falling upon said photo-electric means.

7. A photo-electric device comprising a gastight vessel containing an anode, a glow discharge cathode, a gas filling suflicient to produce copious ionization thereof sufficient to substantially neutralize space charge upon the passage of a discharge between said cathode and anode, means for starting an ionizing discharge between said cathode'and anode at a voltage less than the normal starting voltage, said means comprising photo-electric means separate from said anode and aooaeea cathode and'adap'ted to emit electrons and support a discharge thereto upon excitation by light radiations falling upon said photo-electric means, whereby space currentcarriers are produced upon the occurrence of such a discharge, the production of saidcurrent carriers being suflicient to enable an ionizing discharge to start between said cathode and anode at a voltage less than the normal starting voltage.

8. A photo-electric device comprising a gastight vessel containing an anode, a. glow discharge cathode, a gas filling suflicient to produce copious ionization thereof sufficient to substantially neutralize space charge upon the passage of a discharge between said cathode and anode, means for starting an ionizing discharge between said cathode and anode at a voltage less than the normal starting voltage, said means comprising photo-electric means separate from said anode and cathode and adapted to emit electrons and support a restricted discharge thereto upon excitation by light radiations falling upon said photo-electric means, whereby space current carriers are produced upon the occurrence of such a discharge, the production of said current carriers being suflicient to enable an ionizing discharge to start between said cathode and anode at a voltage less than the normal starting voltage.

' 9. A photo-electric device comprising a gascharge between said cathode and anode, means for starting an ionizing discharge between said cathode and anode at a voltage less than the normal'starting voltage, said means comprising photo-electric means separate from said anode and cathode and adapted to emit electrons and support a discharge thereto upon excitation by light radiationsffalling upon said photo-electric means, whereby space current carriers are produced upon the occurrence of such a discharge, said photoelectric means being disposed adjacent said cathode and anode to admit some of said current carriers'into the discharge space between said cathride and anodeto lower the starting voltage of 

